Fuel cell systems are increasingly used as a power source in a wide variety of applications. Fuel cell propulsion systems have also been proposed for use in vehicles as a replacement for internal combustion engines. The fuel cells generate electricity that is used to charge batteries and/or to power an electric motor. A solid-polymer-electrolyte fuel cell includes a membrane that is sandwiched between an anode and a cathode, referred to as an MEA or membrane electrode assembly. MEA's are sandwiched between conductive separator plates. To produce electricity through an electrochemical reaction, a fuel, commonly hydrogen (H2), but also either methane (CH4) or methanol (CH3OH), is supplied to the anode and an oxidant, such as oxygen (O2) is supplied to the cathode. The source of the oxygen is commonly air.
Several components define a supply line, through which the anode reactant is supplied to the fuel cell stack. Because of the high pressures that these components can experience in traditional fuel cell systems, they must be robust. Further, the components must inhibit diffusion of the anode reactant to atmosphere while under pressure for extended periods of time (e.g., vehicle rest after shutdown). Special materials are traditionally implemented to inhibit anode reactant diffusion. Component cost and size are generally higher than desired because of the robustness and material cost.